Antioxidant for rubber



I Patented Sept. 16,1941

.22 1 9 ANTIOXIDANT v Max Biigeinaiinl Cologne- Mulheim;btto'Bayerv i and-Rudolf Schriiten'Leverkusen; Rhine, and- "Hans Pohler-Cologne-Mulheim; Germany -afs I Sig-hots, by mesne assignment'syto General 1 amine v v Aniline-&iFilm'Gorporation, New'Yorl-r, N.'Y.,' a l a corporation of vDelaware l I No Drawing. -Ap'1i1icati'on October 11,1938, se

3 Claims-n (c1. acc aim en saga mantis-nieces a'aewpradu s which represent a' new class of valuable ana- 'lowing formulaz' 2 s-aligns wherein g stands forgan aromatic radical such a's'phenyl tolyl; xylyl benzyl, anisyl or naphcyclic polymethylene such as cyclopentyl, cyclo- "501 .1 wco pouml have defined y t I I thyl, and R- stands for a radical of a' carbohexyl, alkylcyclohexyl, arylcyclohexyl or tetrahydronaphthyl.

follows from .the foregoing definition the I terms aromatic radical and fra'dical of a carbocyclic polymethylene" are intended to include various substitution products. All these compounds can be prepared ina simple manner by heating a compound of the formula:

LEN-O r n;

- with a compound'of the formula R'.OH or the corresponding ke'tone with hydrogen in the presence of a suitable catalyst such as nickel at a high pressure, It andR' having the same meaning as defined above; r

In the following there respect to some compounds which are charac v teristic of the above class: I

(a) N-phenyl-N'-cyclohexyl-p-phenylene diamine I C H]. H3

CHI-C Whltc'crystals melting point 118-110 (b) N-p-tolyl-N'-cyclohexyl-p-phenylene White crystals melting point 95-96 are given details withvulcanization at 3v atmospheres overpressure and p the mechanical properties of the vulcanizates ob-' diami ne cmcm says/ Y o. white crystals:incitingpoint143- PM new compounds represent vvaluable nu: ox dants or anti-perishing agents for natural 'or artific al rubber, When compared with-the jfld' known diarylarylenei.diamines;which appearrd be related to our compounds from thelchemical point-of view,v they show the following advan-f tages: Our new compounds have a lower melting point andare better soluble in rubber; consequently, they are much less liable to exude from .the composition. They are capable of being easily taken up by rubber and exert an excellentanti- I I perishmg action both towards sun-cracking mechanical influences.

The following examples illustrate the use of our new products in connection with natural orsyn-v thetic rubber and in comparison with priorknown anti-perishmg agents of a similar type the parts being by weight: g

Example 1 A mixture consisting of Parts Smoked sheets 250.00" Crepe r I 250.00 Titanium oxide 100.00 Zinc oxide 50.00 Sulfur"; Diphenyl guanidine l l .25

is divided into 5-parts. One of them ,(test his vulcanized without the addition of an anti-f -perishing agent; the remaining four. parts are vulcanized with 0.75 part each of phenyl-a-naph-.

thylamine (test 2), a mixtureof equal parts of phenyl-a-naphthylamine andcliphenyl-p-phenylene diamine (test 3), N-phenyl-N'-cyclohexyl-pphenylene diamine (test 4) and N-fi-naphthyl N-cyclohexyl-p-phenylene diamine (test 5).

' The following table illustrates the conditions of tained, the first number indicating the tensile w -s-a neag r washerssmash;

I and Til-dam 1 72 a 4 '6 I!!! VULOANIZATION um aolm memo manna loss/e 251 000 0m ans/nee ass/mo 250 70 213675 um zoo/no ammo awe 1 2% 2365656 AI'IIB A a nouns "some" AT 121- 0. AND as Y n'uosrnsnns ovnnrnnssmm no 141 165 150 150 a 108 144 141 us so u 111 1011 AI!!! A 3 DAYS "AGING" IN A Brenna-paws BOMB AT 00' 0. AND AN oxvunn mmssunn or 21 xos. rla ow.

uni-ms m m 201 201 201 DIEM. 1K5 196 201 201 mm. 1a 160 170 171 Example 2 A mixture consisting of Parts A sodium polymerizate of butadiene 100 A mixture of equal parts of colophonium and eaoutchnl 10 Btearlc acid die-thy] amide 5 zinc oxide 7 15 Active carbon black. 40 BenaothiaaolybZ-sulfene diethyl amide 1.5 Sulfur v 1 is divided into 5 parts. One 0! them has been vulcanized without the addition ot an antiperishing agent (test 1)., The remaining tour parts are mixed each with 1% (calculated on the amount of polymerizate) o! phenyl-p -naphthyb amine (test?) 2% o! N-phenyl-N-cYclohexyl-pphenylene diamine (test 3), 1% of N-p-naphthyl- N-cyclohexyl-p-phenylene diamine (test 4), 1% oi N-phenyl-N'-cyclol1exyl-p-phenylene diamine (test 5) and vulcanized for minutes at 2 atmospheres overpressure in the mold. After a 5 days exposure to air and sun tests 1 and 2 show distinct cracks, whereas in case of tests 3 0o 5 much fewer cracks or no cracks at all are to be observed.

We claim:

1. N-phenyl-N-cyclohexyl p phenylene diamine.

2. N-naphthyl-N'-cyclohexyl-p-phenylene diamine.

3. Compounds selected from the class consisting of N-phenyl-N'-cyclohexyl-p-phenylene diamine and N-naphthyi-N'-cyclohexyl-p-phenylene diamine.

MAX 36am. o'rro BAYER.

' RUDOLF ms POHLE. 

